Pitfalls of anatomical aortic valve area measurements using two-dimensional transoesophageal echocardiography and the potential of three-dimensional transoesophageal echocardiography

Multiscale structure and function of the aortic valve apparatus

Whereas studying the aortic valve in isolation has facilitated the development of life-saving procedures and technologies, the dynamic interplay of the aortic valve and its surrounding structures is vital to preserving their function across the wide range of conditions encountered in an active lifestyle. Our view is that these structures should be viewed as an integrated functional unit, here referred to as the aortic valve apparatus (AVA). The coupling of the aortic valve and root, left ventricular outflow tract, and blood circulation is crucial for AVA's functions: unidirectional flow out of the left ventricle, coronary perfusion, reservoir function, and support of left ventricular function. In this review, we explore the multiscale biological and physical phenomena that underlie the simultaneous fulfillment of these functions. A brief overview of the tools used to investigate the AVA, such as medical imaging modalities, experimental methods, and computational modeling, specifically fluid-structure interaction (FSI) simulations, is included. Some pathologies affecting the AVA are explored, and insights are provided on treatments and interventions that aim to maintain quality of life. The concepts explained in this article support the idea of AVA being an integrated functional unit and help identify unanswered research questions. Incorporating phenomena through the molecular, micro, meso, and whole tissue scales is crucial for understanding the sophisticated normal functions and diseases of the AVA.

Practical guidance and clinical applications of transoesophageal echocardiography. A position paper of the working group of echocardiography of the Hellenic Society of Cardiology

Transoesophageal echocardiography (TOE) is a well-established imaging modality, providing more accurate and of higher quality information than transthoracic echocardiography (TTE) for a wide spectrum cardiac and extra-cardiac diseases. The present paper represents an effort by the Echocardiography Working Group (WG) of the Hellenic Cardiology Society to state the essential steps of the typical TOE exam performed in echo lab. This is an educational text, describing the minimal requirements and the preparation of a meticulous TOE examination. Most importantly, it gives practical instructions to obtain and optimize TOE views and analyses the implementation of a combined two-and multi-dimensional protocol for the imaging of the most common cardiac structures during a TOE. In the second part of the article a comprehensive review of the contemporary use of TOE in a wide spectrum of valvular and non-valvular cardiac diseases is provided, based on the current guidelines and the experience of the WG members.

Aortic Valve Planimetry in Aortic Stenosis Quantification: Reliability of Three-Dimensional-Multiplane Reconstruction and Comparison With Established Methods

We aim to evaluate the reliability and consistency of measuring the aortic valve area (AVA) using 3-dimensional (3D) transesophageal echocardiography and compare it with invasive and noninvasive methods using a continuity equation (CE). Measurements were taken from 119 patients with different severity of aortic stenosis and with normal aortic valve who underwent elective transesophageal echocardiography encompassing the whole spectrum of aortic opening. Three methods were compared to determine AVA. First, the effective AVA was calculated with the standard CE, where the left ventricular outflow tract area was calculated from its 2-dimensional diameter (AVA-CEstd). Second, a modified CE method (AVA-CEmod) was used, in which the left ventricular outflow tract area was measured using 3D-multiplane reconstruction. Third, the geometric AVA was directly measured using 3D-multiplane reconstruction planimetry (AVA-3D). Interobserver and intraobserver variability were analyzed using intraclass correlation coefficients (ICCs). The values were measured by two blinded readers for interobserver variability and by one observer on the same dataset. AVA-3D was significantly larger than AVA-CEmod and AVA-CEstd (1.87 ± 1.00 cm2 vs 1.81 ± 0.92 cm2 p = 0.03 and 1.87 ± 1.00 cm2 vs 1.71 ± 0.85 cm2 p <0.001). However, in the subset of patients with AVA-3D <1.5 cm2, there was no significant difference between AVA-3D and AVA-CEmod (1.06 ± 0.24 vs 1.08 ± 0.26 cm2, paired t test: t = 0.77, degree of freedom = 58, p = 0.44). The ICC between the measurements of AVA-3D and AVA-CEmod (ICC 0.979), and AVA-3D and AVA- CEstd (ICC 0.940), were excellent. AVA-3D delivers very similar results as compared with more established echocardiographic parameters. The difference between effective and geometric AVA did not appear to be clinically relevant in patients with a higher degree of stenosis.

Position-based dynamics simulator of vessel deformations for path planning in robotic endovascular catheterization

A major challenge during autonomous navigation in endovascular interventions is the complexity of operating in a deformable but constrained workspace with an instrument. Simulation of deformations for it can provide a cost-effective training platform for path planning. Aim of this study is to develop a realistic, auto-adaptive, and visually plausible simulator to predict vessels' global deformation induced by the robotic catheter's contact and cyclic heartbeat motion. Based on a Position-based Dynamics (PBD) approach for vessel modeling, Particle Swarm Optimization (PSO) algorithm is employed for an auto-adaptive calibration of PBD deformation parameters and of the vessels movement due to a heartbeat. In-vitro experiments were conducted and compared with in-silico results. The end-user evaluation results were reported through quantitative performance metrics and a 5-Point Likert Scale questionnaire. Compared with literature, this simulator has an error of 0.23±0.13% for deformation and 0.30±0.85mm for the aortic root displacement. In-vitro experiments show an error of 1.35±1.38mm for deformation prediction. The end-user evaluation results show that novices are more accustomed to using joystick controllers, and cardiologists are more satisfied with the visual authenticity. The real-time and accurate performance of the simulator make this framework suitable for creating a dynamic environment for autonomous navigation of robotic catheters.

Quantification of aortic valve area: comparison of different methods of echocardiography with 3-D scan of the excised valve

Accurate determination of severity of aortic valve stenosis (AS) by aortic valve area (AVA) is essential for choosing the best treatment strategy. We compared AVA quantified by 4 different in vivo echocardiographic methods with AVA measured by 3D ex vivo scanning of the excised AV. The data on 38 patients who underwent aortic valve replacement were assessed. The AVA was determined by 4 echocardiographic methods of planimetry in 2D transesophageal echocardiography [planimetry (2D-TEE)], plainemetry by multiplanar reconstruction approach in 3D transesophageal echocardiography [MPR (3D-TEE)], and two continuity equation (CE) approaches; conventional CE (2D-TTE) in which left ventricular outflow tract [LVOT] area derived by LVOT diameter obtained in 2D transthoracic echocardiography and CE (3D-TEE) in which LVOT area obtained by 3D MPR. After the surgical removal of the AV, AVA was determined by 3D ex vivo scanning. Lowest AVA mean difference with 3D ex vivo scanning was found between CE (2D-TTE), followed by CE (3D-TEE). Planimetry (2D-TEE) in male patients as well as severely and non-severely calcified valves revealed a significant higher AVA mean difference with 3D ex vivo scanning than CE (2D-TTE) and CE (3D-TEE) methods. However, with a nonsignificant effect, CE (2D-TTE) and planimetry (2D-TEE) had the least mean difference with 3D ex vivo scanning possibly due to less frequent bicuspid AV in females. CE (2D-TTE) was more accurate than other methods of AVA calculation. Moreover, CE (3D-TEE) and MPR (3D-TEE) methods had acceptable accuracy in comparison with planimetry (2D-TEE) for definition of AS severity.

Structural Responses of Integrated Parametric Aortic Valve in an Electro-Mechanical Full Heart Model

The aortic valve (AV) is located between the left ventricle and the aorta and responsible for maintaining an outward unidirectional flow. Many AV hemodynamic and structural aspects of have been extensively studied, however, more sophisticated models are needed to better understand the AV biomechanical behavior. This study deals with integrating a new parametric AV structural model with the electro-mechanical Living Heart Human Model® (LHHM). The LHHM is a finite element model simulating human heart capable of realistic electro-mechanical simulations. Different geometric metrics of AV have been examined. New integrated structural AV model within the LHHM better predict local stresses during the cardiac cycle due to the realistic boundary condition derived from the LHHM. It was found that ellipticity index (EI), calculated as the ratio between the maximal (Max) and minimal (Min) aortic annulus (AA) diameters, well correlates with measured clinical data obtained from patients undergoing computed tomography (CT) while the annular perimeter (Perim) matches the same trend. This increases the confidence in the predicted kinematic behavior, leaflets coaptation, and the overall stresses. From the clinical aspect, the new proposed coupled and integrated AV modeling can serve as a platform for design and implementation of pre-transcatheter aortic valve replacement (TAVR) procedures.

Traumatic aorto-pulmonary artery fistula: a case report

Background 

Aorta-pulmonary (A-P) artery fistula following a stab wound to the chest with superimposed infective endocarditis (IE) is a rare, often unrecognized presentation. Herein, we report a case of A-P fistula due to stab chest assessed by two- and three-dimensional (3D) imaging.

Case summary 

A 30-year-old man presented with a history of being stabbed in the chest with a screwdriver. The chest wall laceration was sutured, an intercostal drain inserted for a haemopneumothorax, and he was subsequently discharged. He presented 3 weeks later with exertional dyspnoea, fever, rigours, and loss of weight. On examination, he had a wide pulse pressure and a harsh continuous murmur in the 2nd left intercostal space associated with a palpable thrill. Blood tests revealed raised infective markers and anaemia. All blood cultures were sterile. On echocardiography, the aortic and pulmonary valve was severely damaged, with suspicion of superimposed vegetations secondary to IE. There was severe aortic and pulmonary valve regurgitation. A fistulous connection was noted between the aorta and main pulmonary artery, just below the commissure adjoining the right and left coronary sinus of the aortic valve. On 3D imaging, the defect was quantified. The patient was subsequently referred for aortic and pulmonary valve replacement and closure of the A-P fistula. The presence of multiple vegetations was confirmed intraoperatively. He also received a 6-week course of intravenous antibiotics.

Discussion 

We have described a rare case of an A-P fistula due to a stab wound to the chest complicated by IE. In a patient with stab wound to the chest, a high index of suspicion of cardiac involvement must be maintained, and a careful search for intracardiac shunts must be made on echocardiography, prior to discharge. Furthermore, in addition to two-dimensional imaging, 3D imaging proved useful in providing a comprehensive assessment of the morphology of the lesion prior to surgery.

Expert consensus document on the assessment of the severity of aortic valve stenosis by echocardiography to provide diagnostic conclusiveness by standardized verifiable documentation

According to recent recommendations on echocardiographic assessment of aortic valve stenosis direct measurement of transvalvular peak jet velocity, calculation of transvalvular mean gradient from the velocities using the Bernoulli equation and calculation of the effective aortic valve area by continuity equation are the appropriate primary key instruments for grading severity of aortic valve stenosis. It is obvious that no gold standard can be declared for grading the severity of aortic stenosis. Thus, conclusions of the exclusive evaluation of aortic stenosis by Doppler echocardiography seem to be questionable due to the susceptibility to errors caused by methodological limitations, mathematical simplifications and inappropriate documentation. The present paper will address practical issues of echocardiographic documentation to satisfy the needs to analyze different scenarios of aortic stenosis due to various flow conditions and pressure gradients. Transesophageal and multidimensional echocardiography should be implemented for reliable measurement of geometric aortic valve area and of cardiac dimensions at an early stage of the diagnostic procedure to avoid misinterpretation due to inconsistent results.

Contemporary Imaging of Aortic Stenosis

Degenerative or fibrocalcific aortic stenosis (AS) is now the most common native valvular heart disease assessed and managed by cardiologists in developed countries. Transthoracic echocardiography remains the quintessential imaging modality for the non-invasive characterisation of AS due to its widespread availability, superior assessment of flow haemodynamics, and a wealth of prognostic data accumulated over decades of clinical utility and research applications. With expanding technologies and increasing availability of treatment options such as transcatheter aortic valve replacements, in addition to conventional surgical approaches, accurate and precise assessment of AS severity is critical to guide decisions for and timing of interventions. Despite clear guideline echocardiographic parameters demarcating severe AS, discrepancies between transvalvular velocities, gradients, and calculated valve areas are commonly encountered in clinical practice. This often results in diagnostically challenging cases with significant implications. Greater emphasis must be placed on the quality of performance of basic two dimensional (2D) and Doppler measurements (attention to detail ensuring accuracy and precision), incorporating ancillary haemodynamic surrogates, understanding study- or patient-specific confounders, and recognising the role and limitations of stress echocardiography in the subgroups of low-flow low-gradient AS. A multiparametric approach, along with the incorporation of multimodality imaging (cardiac computed tomography or magnetic resonance imaging) in certain scenarios, is now mandatory to avoid incorrect misclassification of severe AS. This is essential to ensure appropriate selection of patients who would most benefit from interventions on the aortic valve to relieve the afterload mismatch resulting from truly severe valvular stenosis.

Newer echocardiographic techniques for aortic-valve imaging: Clinical aids today, clinical practice tomorrow

Increasing life expectancy is expected to lead to a corresponding increase in the prevalence of aortic valve disease (AVD). Further, the number of indications for transcatheter aortic valve replacement (TAVR) as a treatment option for AVD is expanding, with a growing role for echocardiography in its management. In this review we summarize the current literature on some newer echocardiographic modalities and the parameters they generate, with a particular focus on their prognostic and clinical value beyond conventional methods in the management of aortic stenosis, TAVR, and aortic regurgitation. Speckle tracking and 3D echocardiography are now increasingly being used in the management of AVD. For instance, global longitudinal strain, the best-studied speckle tracking echocardiographic parameter, can detect subtle subclinical cardiac dysfunction in patients with AVD that is not apparent using traditional echocardiographic techniques. The emerging technique of 3D full volume color Doppler echocardiography provides more accurate measurement of the severity of aortic regurgitation than 2D-proximal isovelocity surface area. These novel techniques are promising for evaluating and risk stratifying patients to optimize surgical interventions, predict recovery, and improve clinical outcomes.

Echocardiographic 3D-guided 2D planimetry in quantifying left-sided valvular heart disease

Echocardiographic 3D-guided 2D planimetry can improve the accuracy of valvular disease assessment. Acquisition of 3D pyramidal dataset allows subsequent multiplanar reconstruction with accurate orthogonal plane alignment to obtain the correct borders of an anatomic orifice or flow area. Studies examining the 3D-guided 2D planimetry approach in left-sided valvular heart disease were identified and reviewed. The strongest evidence exists for estimating mitral valve area in patients with rheumatic mitral valve stenosis and vena contracta area in patients with mitral regurgitation (both primary and secondary). 3D-guided approach showed excellent feasibility and reproducibility in most studies, as well as time efficiency and good correlation with reference and comparator methods. Therefore, 3D-guided 2D planimetry can be used as an important clinical tool in quantifying left-sided valvular heart disease, especially mitral valve disorders.

Dynamic Three-Dimensional Geometry of the Aortic Valve Apparatus-A Feasibility Study

OBJECTIVE

To provide (1) an overview of the aortic valve (AV) apparatus anatomy and nomenclature, and (2) data regarding the normal AV apparatus geometry and dynamism during the cardiac cycle obtained from three-dimensional transesophageal echocardiography (3D TEE).

DESIGN

Retrospective feasibility study.

SETTING

A single-center university teaching hospital.

PARTICIPANTS

The study was performed on data of 10 patients with a nonregurgitant, nonstenotic aortic valve undergoing cardiac surgery.

INTERVENTIONS

Intraoperative 3D TEE was performed on all the participants using the Siemens ACUSON SC2000 ultrasound system and Z6Ms transducer (Siemens Medical Systems, Mountainview, CA).

MEASUREMENTS AND MAIN RESULTS

Dynamic offline analyses were performed with Siemens eSie valve analytical software in a semiautomated fashion. Forty-five parameters were exported of which 13 were selected and analyzed. The cardiac cycle was divided into 4 quartiles to account for frame-rate variations. The annulus, sinus of Valsalva (SoV) and sinotubular junction (STJ) areas, diameter, perimeter and height, aortic leaflet height, leaflet coaptation height, and aortic valve-mitral valve angle changed significantly during the cardiac cycle (p < 0.001). STJ expanded more than both the annulus and the SoV (p < 0.001). The maximum aortic valve leaflet height change was greater in the left and right versus noncoronary leaflet (p < 0.001).

CONCLUSIONS

The semiautomated AV apparatus dynamic assessment using eSie valve software is a clinically feasible technique and can be performed readily in the operating room. It has the potential to significantly impact intraoperative decision-making in cases suitable for AV repair. The AV apparatus is a dynamic structure and demonstrates significant changes during the cardiac cycle.

Anterior Aortic Plane Systolic Excursion: A Novel Indicator of Transplant-Free Survival in Systemic Light-Chain Amyloidosis

BACKGROUND

Anterior aortic plane systolic excursion (AAPSE) was evaluated in the present pilot study as a novel echocardiographic indicator of transplant-free survival in patients with systemic light-chain amyloidosis.

METHODS

Eighty-nine patients with light-chain amyloidosis were included in the post-hoc analysis. A subgroup of 54 patients with biopsy-proven cardiac amyloid infiltration were compared with 41 healthy individuals to evaluate the discriminative ability of echocardiographic findings. AAPSE is defined as the systolic excursion of the anterior aortic margin. To quantify AAPSE, the M-mode cursor was placed on the aortic valve plane in parasternal long-axis view at end-diastole. Index echocardiography had been performed before chemotherapy. Median follow-up duration was 2.4 years. The primary combined end point was heart transplantation or overall death.

RESULTS

Mean AAPSE was 14 ± 2 mm in healthy individuals (mean age=57 ± 10 years; 56% men; BMI=25 ± 4 kg/m²). AAPSE < 11 mm separated patients from age-, gender-, and BMI-matched control subjects with 93% sensitivity and 97% specificity. Median transplant-free survival of patients with AAPSE < 5 mm was 0.7 versus 4.8 years (P = .0001). AAPSE was an independent indicator of transplant-free survival in multivariate Cox regression (echocardiographic model: hazard ratio=0.72 [P = .03]; biomarker model: hazard ratio=0.62 [P = .0001]). Sequential regression analysis suggested incremental power of AAPSE as a marker of transplant-free survival. An ejection fraction-based model with an overall χ² value of 22.8 was improved by the addition of log NT-proBNP (χ² = 32.6, P < .005), troponin-T (χ² = 39.6, P < .01), and AAPSE (χ² = 54.0, P < .0001).

CONCLUSIONS

AAPSE is suggested as an indicator of transplant-free survival in patients with systemic light-chain amyloidosis. AAPSE provided significant incremental value to established staging models.

Diagnosis and management of patients with asymptomatic severe aortic stenosis

Aortic stenosis (AS) is a disease that progresses slowly for years without symptoms, so patients need to be carefully managed with appropriate follow up and referred for aortic valve replacement in a timely manner. Development of symptoms is a clear indication for aortic valve intervention in patients with severe AS. The decision for early surgery in patients with asymptomatic severe AS is more complex. In this review, we discuss how to identify high-risk patients with asymptomatic severe AS who may benefit from early surgery.

The times they are a-changin': Two-dimensional aortic valve measurements differ throughout diastole

INTRODUCTION

Diastolic aortic valve measurements are used to obtain weight-independent cardiac ratiometric indices. However, whether clinically important variations in valve measurements occur during diastole remains undetermined.

ANIMALS

One hundred sixty-three dogs and 40 cats; a mixture of healthy animals and patients with heart disease.

MATERIALS AND METHODS

Aortic valve diameter and area were measured at three time-points: early diastole {AoMAX}, during the P-wave {AoP} and at end-diastole {AoMIN}. Measurement beat-to-beat variability was determined. Difference plots were generated for each measurement pair. Aortic measurements were compared by repeated measures analysis of variance.

RESULTS

In dogs, normalised aortic diameters showed a fixed bias of approximately 14% for AoMAX-AoMIN, 6% for AoMAX-AoP and 8% for AoP-AoMIN. In cats, the aortic diameter and area biases were all less than 2.5% and less than 7% respectively. AoMAX was the largest measurement in 78% patients and AoMIN was the smallest measurement in 73% patients. In dogs, AoMAX > AoP > AoMIN (p < 0.0001). Median within-patient measurement variability was 5% for linear dimensions and 8% for area measurements in dogs and 4.5% for linear and 10.4% for area in cats.

DISCUSSION

Aortic measurements in dogs differ significantly throughout diastole, with Ao(A)MAX > Ao(A)P > Ao(A)MIN. These differences could clinically impact cardiac ratiometric indices. The difference in cats is less than the within-patient measurement variability and unlikely to be of clinical significance.

CONCLUSIONS

Operators should adopt a single diastolic time-point for measurement of the aorta to ensure consistency in measuring and reporting in echocardiography.

[Application fields of intraoperative transesophageal 3D echocardiography]

Intraoperative transesophageal echocardiography (TEE) is an established diagnostic tool and has to be regarded as the standard of care for intraoperative monitoring and cardiac surgical decision-making. Furthermore, intraoperative TEE is also used for monitoring and assessment of hemodynamic changes and the detection of previously unknown pathologies. In the past few years 3D-TEE has extended the spectrum of 2D-TEE by allowing pathomorphological features to be more easily and intuitively linked to the anatomy of the heart and the great vessels. Thus, a comprehensive 2D-TEE examination is favorably complemented by focused 3D-TEE. Especially during mitral valve surgery, 3D-TEE has proven its superiority in the diagnosis of the underlying pathology as demonstrated by a large number of studies in this field. This review presents the available data about the role of intraoperative 3D-TEE echocardiography and introduces practical fields of application.

Low gradient aortic stenosis

OPINION STATEMENT

Severe low-gradient (LG) aortic stenosis (AS) [aortic valve area (AVA) ≤ 1.0 cm(2), mean pressure gradient (MG) < 40 mmHg] represents a frequently encountered and challenging clinical dilemma. A systematic approach, which often requires several imaging modalities, should be undertaken to confirm the hemodynamic findings and rule out measurement error. Low-flow conditions often account for the discrepancy and can be present whether the left ventricular ejection fraction (LVEF) is depressed or normal. In patients with classical low-flow (LF), LG AS in which LVEF is reduced (<40-50 %), dobutamine stress echocardiography (DSE) should be used to distinguish patients with true severe AS and pseudo-severe AS, as well as to evaluate for the presence of left ventricular contractile or flow reserve. Surgical or transcatheter aortic valve replacement (AVR) should likely be reserved for those patients with true severe AS. Patient outcome with medical or surgical management generally relates to patient functional capacity, stenosis severity, and left ventricular functional reserve. Patients with severe LG AS with preserved LVEF can have a stroke volume that is either normal (>35 mL/m(2)) or low (<35 mL/m(2)). New data suggest that DSE can identify pseudo-severe AS in up to 30 % of patients with severe LF-LG AS with preserved LVEF. AVR should likely be restricted to those patients with true severe AS, although there is currently little data to support this strategy. Symptomatic patients with severe LG AS with preserved LVEF, whether they have normal or low flow, should be offered AVR. Transcatheter AVR provides an alternative therapeutic option in the high-risk patient.

Echocardiographic Evaluation of Aortic Stenosis - Normal Flow and Low Flow Scenarios

The echocardiographic evaluation of the patient with aortic stenosis (AS) has evolved in recent years, beyond confirming the diagnosis and measuring the resting mean pressure gradient or valve area. New echocardiographic approaches have developed to address the clinical dilemmas related to discordant haemodynamic data, asymptomatic haemodynamically severe AS and low-flow, low-gradient AS in order to better evaluate the disease severity, enhance the risk stratification of patients and provide important prognostic information. This article reviews the echocardiographic evaluation of the AS patient and focuses on the echocardiographic assessment of the haemodynamic severity, the prediction of clinical outcome and the use of echocardiography to guide patient management in the presence of normal flow and low flow scenarios.

Calcific extension towards the mitral valve causes non-rheumatic mitral stenosis in degenerative aortic stenosis: real-time 3D transoesophageal echocardiography study

Objective

Mitral annular/leaflet calcification (MALC) is frequently observed in patients with degenerative aortic stenosis (AS). However, the impact of MALC on mitral valve function has not been established. We aimed to investigate whether MALC reduces mitral annular area and restricts leaflet opening, resulting in non-rheumatic mitral stenosis.

Methods

Real-time three-dimensional transoesophageal images of the mitral valve were acquired in 101 patients with degenerative AS and 26 control participants. The outer and inner borders of the mitral annular area (MAA) and the maximal leaflet opening angle were measured at early diastole. The mitral valve area (MVA) was calculated as the left ventricular stroke volume divided by the velocity time integral of the transmitral flow velocity.

Results

Although the outer MAA was significantly larger in patients with AS compared to control participants (8.2±1.3 vs 7.3±0.9 cm², p<0.001), the inner MAA was significantly smaller (4.5±1.1 vs 5.9±0.9 cm², p<0.001), resulting in an average decrease of 45% in the effective MAA. The maximal anterior and posterior leaflet opening angle was also significantly smaller in patients with AS (64±10 vs 72±8°, p<0.001, 71±12 vs 87±7°, p<0.001). Thus, MVA was significantly smaller in patients with AS (2.5±1.0 vs 3.8±0.8 cm², p<0.001). Twenty-four (24%) patients with AS showed MVA <1.5 cm². Multivariate regression analysis including parameters for mitral valve geometry revealed that a decrease in effective MAA and a reduced posterior leaflet opening angle were independent predictors for MVA.

Conclusions

Calcific extension to the mitral valve in patients with AS reduced effective MAA and the leaflet opening, resulting in a significant non-rheumatic mitral stenosis in one-fourth of the patients.

Assessment of aortic and mitral annuli dynamics during the cardiac cycle using speckle tracking echocardiography

The aims of this study were i) to evaluate mitral and aortic annuli excursion, and aortomitral angle (AMA) during the cardiac cycle in healthy adults using two-dimensional speckle tracking echocardiography, ii) to assess two annuli dynamics and coupling behaviors as an integral, and iii) to detect the relation between two annuli and left ventricular ejection fraction (LVEF). A total of 74 healthy adults underwent transthoracic echocardiography. In the parasternal long-axis view, a number of points were extracted, including right coronary aortic annular, aortomitral fibrous junction, and posterior mitral annular points. The annuli excursion and AMA were measured using a speckle tracking-derived software during the cardiac cycle. During the isovolumic contraction and the isovolumic relaxation phase, annuli excursion and AMA remain stable for a short time. During the systole, annuli excursion increased sharply to the maximum, while AMA narrowed quickly to the minimum value. During the diastole, there are three patterns of decrease in annuli excursion and AMA expansion in different phases. The annuli excursion of three points correlates well with the LVEF (right coronary aortic annulus excursion, r=0.71, P<0.05; non-coronary aortic annulus excursion, r=0.70, P<0.05; posterior mitral annulus excursion, r=0.82, P<0.05). Moreover, there are positive correlations between annuli excursion and the variation of AMA (r=0.60, P<0.05). The annuli excursion and AMA have various regular patterns in healthy adults. The interactions of mitral and aortic annuli correlate with the left ventricular function. Our findings may have relevance to the evaluation of left ventricular function and presurgical planning of patients with valvular diseases.

Feasibility of in vivo human aortic valve modeling using real-time three-dimensional echocardiography

BACKGROUND

Surgical techniques for aortic valve (AV) repair are directed toward restoring normal structural relationships in the aortic root and rely on detailed assessment of root and valve anatomy. Noninvasive three-dimensional (3D) imaging and modeling may assist in patient selection and operative planning.

METHODS

Transesophageal real-time 3D echocardiographic images of 5 patients with normal AVs were acquired. The aortic root and the annulus were manually segmented at end diastole using a 36-point rotational template. The AV leaflets and the coaptation zone were manually segmented in parallel 1-mm cross sections. Quantitative 3D models of the AV and root were generated and used to measure standard anatomic parameters and were compared to conventional two-dimensional echocardiographic measurements. All measurements are given as mean±SD.

RESULTS

Annular, sinus, and sinotubular junction areas were 4.1±0.6 cm2, 7.5±1.2 cm2, and 3.9±1.0 cm2, respectively. Root diameters (measured in three locations) by 3D model inspection and two-dimensional echocardiography measurement correlated (R2=0.75). Noncoapted areas of the left, right, and noncoronary leaflets were 1.9±0.2 cm2, 1.6±0.3 cm2, and 1.6±0.3 cm2, respectively. Mean coaptation areas for the left-right, left-noncoronary, and right-noncoronary coaptation zones were 87.7±36.9 mm2, 69.9±20.7 mm2, and 114.2±23.0 mm2, respectively. The mean ratio of noncoapted leaflet area to annular area was 1.3±0.2.

CONCLUSIONS

High-resolution 3D models of the in vivo normal human aortic root and valve were generated using 3D echocardiography. Quantitative 3D models and analysis may assist in characterization of pathology and decision making for AV repair.

Quantitative Analysis of Aortic Valve Stenosis and Aortic Root Dimensions by Three-Dimensional Echocardiography in Patients Scheduled for Transcutaneous Aortic Valve Implantation

Accurate assessment of the aortic valve area (AVA) and evaluation of the aortic root are important for clinical decision-making in patients being considered for transcatheter aortic valve implantation (TAVI). Real-time three-dimensional transesophageal echocardiography (RT3D-TEE) provides accurate and reliable quantitative assessment of aortic valve stenosis and the aortic root. We performed two-dimensional transthoracic echocardiography (2D-TTE), real-time 2D transesophageal echocardiography (RT2D-TEE) and RT3D-TEE in 71 consecutive patients referred for TAVI. RT3D-TEE multiplanar reconstruction was used to measure aortic root parameters, including left ventricular outflow tract (LVOT) diameter and area, aortic annulus diameter, aortic annulus area, and AVA. RT3D-TEE methods for planimetry and the LVOT-derived continuity equation for the estimation of AVA showed a good correlation. As iatrogenic coronary ostium occlusion is a potentially life-threatening complication, we evaluated the distances from the aortic annulus to the coronary ostia using RT3D-TEE. Based on our findings, we conclude that the geometry of the aortic root and aortic valve can be reliably and feasibly evaluated using RT3D-TEE, which is important for protecting against potential complications of TAVI, such as underestimation of the size of the aortic annulus that can result in aortic regurgitation and dislocation of the valve, or overestimation can lead to annulus rupture.

Assessment of cyclic changes in the diameter of the aortic annulus using speckle-tracking trans-esophageal echocardiography

It is uncertain whether dynamic variation in the diameter of the aortic annulus occurs during the cardiac cycle in humans. The purpose of this study was to analyze cyclic changes of the aortic annulus using speckle-tracking trans-esophageal echocardiography. The subjects were 40 patients with aortic stenosis and 40 controls. Absolute and relative changes in the diameter of the aortic annulus and the times at which the maximum and minimum diameters occurred during the cardiac cycle were determined using speckle-tracking trans-esophageal echocardiography. The maximum and minimum diameters were 22.9 ± 2.7 and 20.0 ± 2.9 mm, respectively, in controls. The change in diameter of the aortic annulus was 2.9 ± 0.7 mm, and the relative change was 12.9 ± 3.5%. The maximum aortic annulus diameter was reached at the onset of aortic valve opening, and the minimum diameter occurred in the rapid filling phase. The change in diameter of the aortic annulus was significantly smaller (2.2 ± 0.6 mm vs. 2.9 ± 0.7 mm, p < 0.0001), and the time to reach the maximum diameter was significantly longer (98.5 ± 17.5 ms vs. 83.4 ± 18.2 ms, p = 0.0004), in the aortic stenosis group than in the control group. The study found that dynamic changes of the aortic annulus occur in the cardiac cycle and can be measured using speckle-tracking trans-esophageal echocardiography. We also found that aortic stenosis has an effect on the extent and timing of these changes. This suggests that accurate assessment of aortic annulus diameter requires consideration of the timing of the cardiac cycle.

Advanced echocardiographic techniques

Echocardiography has advanced significantly since its first clinical use. The move towards more accurate imaging and quantification has driven this advancement. In this review, we will briefly focus on three distinct but important recent advances, three‐dimensional (3D) echocardiography, contrast echocardiography and myocardial tissue imaging. The basic principles of these techniques will be discussed as well as current and future clinical applications.

Review of novel clinical applications of advanced, real-time, 3-dimensional echocardiography

Advances in computer processing speed and memory along with the advent of the microbeam former that can sample an entire crystal of the ultrasound transducer made possible the performance of 3-dimensional echocardiography in real time (RT3DE). The miniaturization of a 3-dimensional transducer permitting its extension to transesophageal mode rapidly expanded its use in a variety of conditions. Recent development of user-friendly automated/semiautomated cropping and display software may make it rather simple, even for the novice to gather useful information from RT3DE. We discuss the background, technique, and cutting-edge research and novel clinical applications of advanced RT3DE, including left ventricular dyssynchrony assessment, 3-D speckle tracking, myocardial contrast echocardiography, complete 4-dimensional (4-D) shape and motion analysis of the left ventricle, 4-D volumetric analysis of the right ventricle, 3-D volume rendering of the mitral valve, and other percutaneous and surgical procedural applications.